Current ensemble forecasts place Qingdao’s September 21 minimum near 19–22 °C under partly cloudy skies and light variable winds, producing the market’s near-even odds across bins. The primary driver is the absence of strong cold advection or nocturnal radiative cooling, as southerly flow off the Yellow Sea maintains mild marine air while limited cloud cover allows moderate daytime heating followed by gradual overnight decline. Model spread arises from subtle differences in timing of any thin cloud deck or wind shift, which can alter the low by 1–2 °C. Historical September minima average near 18–20 °C, providing context for the tight clustering around 20 °C. Updated China Meteorological Administration runs and local station observations on the 20th–21st will refine the exact threshold before resolution.